What is the leopard evolutionary tree?

Nobody knows.

Leopards are felids in the genus Panthera. The last common ancestor for animals in this genus is generally believed to have lived about six and a half million years ago. Leopards appear to be related to lions, tigers, snow leopards, jaguars, and clouded leopards, but the exact details are not entirely clear.

They're more distantly related to the other felids (cats, cheetahs), and even more distantly related to other feliforms like hyenas and mongooses.

One thing that makes it tricky is that fossils of all felids tend to look pretty much alike, with the most notable distinction usually being size, and there are a number of extinct species which must have looked very similar to cats despite being rather more closely related to kangaroos.